Improvement in book-supports



A. CLARKE. Book-Support.

No. 197,763. Patented Dec. 4,1 77.

INVENTO2 WITNESSES: I i

ATTORNEYS.

N4 PETERS, PHOTO-LITHO .iRAFHER, WASHINGTON. D, Cv

UNITED STATES PATENT OFFICE.

' ALMON CLARKE, OF SHEBOYGAN, WISCONSIN, ASSIGNOR TO HIMSELF AND CHARLESA. SPENCER, OF SAME PLACE.

'IIVIPROVEMENT IN BOOK-SUPPORTS.

Specification forming part of Letters Patent No. 197,763, dated December4, 1877; application filed July 23, 1877.

is a specification In the accompanying drawing, Figure 1 represents aside viewof my improved adjustable book-rest for chairs. Figs.2, 3, and4 are, respectively, a rear view, top view, and an end View, partly insection, on line w on, Fig. 1, of the guide-clamp attached to chair.Fig. 5 is a top view of the upper clamp for regulating position of desk.Fig. 6 is a top view of deskholding screw-post and plate. Fig.7 is aside view of the entire device on smaller scale, shown as attached to anarm-chair.

Similar letters of reference indicate corresponding parts.

The object of this invention is to furnish a simple and cheap book-restor adjustable desk, to be attached to the arm of a chair or othersupport, and be conveniently adjusted as to height and inclinationtoward the reader.

The invention consists of a double supporting-arm, which is adjustableas to height and angle of inclination on a screw-post of the chair by atoothed clamp and guide device, the bookrest being adjusted by a secondtoothed clamp device at the upper end of the supporting-arm.

In the drawing, A represents a double supporting-arm, of suitable lengthand strength, which is preferably made of a wrought-iron rod that isbentinto U shape, as shown inFig.1. The lower end of the double armA isclamped to a screw-post, B, that is rigidly attached to the chair orother object by a base-piece, C, secured by fastening screws. On thebasepiece C is placed a disk, D, that is recessed at the rear side, soas to fit and bind on the basepiece C, and provided with radial teeth atthe front side. A clamp-piece, E, that is placed on the top of thesupporting-arm A,is grooved at the under side to bind on the double armA, and provided with a solid guide portion, a, at one or both ends, thatproject through the space between the double arm, and interlock by oneor more teeth with the face-teeth of the disk D.

A thumb-nut, E, binds on the clamppiece E, and clamps the toothed disk,supporting arm, and clamp-piece rigidly together. By loosening thethumb-nut the supporting-arm may be readily raised or lowered by beingmoved along the grooved clamp and guidepiece E, and also adjusted to anydesired angle toward the point of support, by means of I the toothedportion of the clamp-piece and toothed base-disk turning on thescrew-post.

The height and angle of the book-rest are thus adjusted by the slidingarm and lower clamp device.

The book-rest or desk F is connected to the upper end of thesupporting-arm A by a screwpost, F, passing through the solid endcasting A of arm A. The screw-postF is rigidly attached, by an end diskof plate F and fastening-screws, to back of the book-rest or desk. Theend casting A is provided at the side facing the desk F with teeth d,radiating from the hole for the screwpost, and interlocking with one ormore teeth, 01-, of the bracket or shoulder of the disk plate F fromwhich the screw-post F extends. Athumb-nut, G, binds the end casting Aand screw-post F together, and adjusts, by the interlocking toothedportions, the book-rest F to any desired angle of inclination on thesupporting-arm. In place of the thumb-nut,a set-screw passing throughsolid end into the post may be used. The book-rest may thus, by thesupporting-arm and the lower and upper clamp devices, be set into themanner set forth.

ALMON CLARKE. Witnesses:

J. D. SrEARNs, D. W. HALSTED.

